Effect of progestogen (Depo-Provera) on annulate lamellae in endometrial carcinoma

The authors studied electron microscopically the effect of a large dose of medroxyprogesterone acetate (Depo-Provera) on the fine structure of endometrial carcinoma, with special regard to the annulate lamellae of the cells. Following treatment in one-third of their cases of highly-differentiated endometrial carcinoma the glandular epithelial cells were found to show a marked regression. After using a large dose of progestogen, the oestrogen-dependent annulate lamellae 'disappeared' from the cytoplasm of the cells. This phenomenon may be one of the morphological manifestations of subcellular oestrogen-progesterone antagonism.